Does chocolate have any positive effect if eaten while I'm sick?!

If you have stomach related sickness then chocolates are bad for you.
During other sicknesses they can come in handy as high calorie food. Like when everything tastes bad and you don't feel like eating anything else. Specially effective when recovering after fever.

Chocolates are usually milk products thus high in calcium too.

No, it may actually depress you and chemically can upset your stomach easily. An benefits it has on your body can be found in other halthier foods and in higher quantities.

University of Michigan Medical School.

You should stay away from chocolate when your sick. It's high in sugar and also has caffeine in it and milk as well.